A laser printer is a printer that uses a focused beam or light on paper to transfer text and images.
However, a popular belief of the people is exactly the opposite, that they feel that the laser actually burns the images on paper. But this is not the case at all, because when paper passes from the printer, then there is a laser beam fire in the surface of a cylindrical drum which is called a photo-receptor.
This drum has an electrical charge (typically positive), which goes reverse in the areas where the laser beam hits. In some places on the drum due to this type of charge reversing, the laser beam can easily print patterns (such as text and pictures) on the photo-receptor.
Once the pattern is created on the drum, then it is coated in toner, which comes from a toner cartridge. These toners are mostly black in all cartridges, but in some places they are also cyan, magenta, and yellow in color laser printers.
These positively charged toner cling to the drum in those areas which are negatively charged by laser. When the paper passes through the printer, then the drum is provided with a strong negative charge, which allows the toner to transfer and stick to the paper. As a result, a clean copy image is printed in the paper.
Since laser printers do not use ink, they have fewer image smearing problems than an inkjet printers and are able to print pages much faster.
While laser printers and toner cartridges are typically more expensive than inkjet printers and ink cartridges, most laser toner cartridges run much more than other ink cartridges, making their cost per page the same.
This is why businesses often use laser printers, while consumers often use inkjet printers. Laser printers typically have a resolution of 600 dpi (dots per inch) or even more.